The present invention relates to a bearing retainer for use in a sliding mechanism of a machine tool, particularly a press.
A die-set is generally used to improve precision in press working, such as punching or bending. The die-set includes a punch holder to hold a punch, a die holder facing the punch holder to hold a die and a guide-post as a sliding mechanism which slidably supports each holder. The guide-post includes a longitudinally extending post, a sleeve slidably received outside the post and a bearing inserted between the post and the sleeve.
As shown in FIG. 12, a conventional bearing 100 for a guide-post includes a generally cylindrical retainer 101 and a plurality of balls 102 received in the retainer 101. Each ball 102 is rotatably received in each hole 103 formed in the retainer 101.
Each hole 103 of the retainer 101 is formed by drilling a pipe. A drilled hole 103, as shown in FIG. 13A, has a tongue-like portion 105 protruding inwardly from the edge of the hole 103 on the inner side surface 101a of the retainer 101. The ball 102 is then inserted into the hole 103 from the outer side surface 101b of the retainer 101.
After the ball 102 is inserted into the hole 103 a caulking tool 110 is pressed around the adjacent part of the edge of the hole 103 on the outer side surface 101b of the retainer 101. As a result of this caulking, as shown in FIG. 13B, a tongue-like portion 107 similar to the tongue-like portion 105 is formed around the edge of the hole 103 on the outer side surface 101b of the retainer 101. These tongue-like portions 105, 107 hold the ball 102 inside the hole 103 and prevent the ball 102 from dropping out of the hole 103.
As described above, caulking process as well as drilling process is required in manufacturing a prior art bearing retainer for use in the guide-post of the die-set. This increases the manufacturing cost of the bearing retainer.
It is the primary object of the present invention to provide a bearing retainer for use in a sliding mechanism of a machine tool, particularly a press, which can decrease the manufacturing cost.